org.apache.lucene.index
Class FilterIndexReader

java.lang.Object
  org.apache.lucene.index.IndexReader
      org.apache.lucene.index.FilterIndexReader

All Implemented Interfaces:

Closeable, Cloneable

Direct Known Subclasses:

MultiPassIndexSplitter.FakeDeleteIndexReader

public class FilterIndexReader
extends IndexReader

A FilterIndexReader contains another IndexReader, which it uses as its basic source of data, possibly transforming the data along the way or providing additional functionality. The class FilterIndexReader itself simply implements all abstract methods of IndexReader with versions that pass all requests to the contained index reader. Subclasses of FilterIndexReader may further override some of these methods and may also provide additional methods and fields.

Nested Class Summary

static class	FilterIndexReader.FilterTermDocs Base class for filtering TermDocs implementations.
static class	FilterIndexReader.FilterTermEnum Base class for filtering TermEnum implementations.
static class	FilterIndexReader.FilterTermPositions Base class for filtering TermPositions implementations.

Nested classes/interfaces inherited from class org.apache.lucene.index.IndexReader

IndexReader.FieldOption, IndexReader.ReaderFinishedListener

Field Summary

protected IndexReader

in

Fields inherited from class org.apache.lucene.index.IndexReader

hasChanges, readerFinishedListeners

Constructor Summary

FilterIndexReader(IndexReader in)
Construct a FilterIndexReader based on the specified base reader.

Method Summary

void	addReaderFinishedListener(IndexReader.ReaderFinishedListener listener) Expert: adds a IndexReader.ReaderFinishedListener.
Directory	directory() Returns the directory associated with this index.
int	docFreq(Term t) Returns the number of documents containing the term t.
protected void	doClose() Implements close.
protected void	doCommit(Map<String,String> commitUserData) Implements commit.
Document	document(int n, FieldSelector fieldSelector) Get the Document at the n th position.
protected void	doDelete(int n) Implements deletion of the document numbered docNum.
protected void	doSetNorm(int d, String f, byte b) Implements setNorm in subclass.
protected void	doUndeleteAll() Implements actual undeleteAll() in subclass.
Object	getCoreCacheKey() If the subclass of FilteredIndexReader modifies the contents of the FieldCache, you must override this method to provide a different key
Object	getDeletesCacheKey() If the subclass of FilteredIndexReader modifies the deleted docs, you must override this method to provide a different key
Collection<String>	getFieldNames(IndexReader.FieldOption fieldNames) Get a list of unique field names that exist in this index and have the specified field option information.
IndexReader[]	getSequentialSubReaders() Expert: returns the sequential sub readers that this reader is logically composed of.
TermFreqVector	getTermFreqVector(int docNumber, String field) Return a term frequency vector for the specified document and field.
void	getTermFreqVector(int docNumber, String field, TermVectorMapper mapper) Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of the TermFreqVector.
void	getTermFreqVector(int docNumber, TermVectorMapper mapper) Map all the term vectors for all fields in a Document
TermFreqVector[]	getTermFreqVectors(int docNumber) Return an array of term frequency vectors for the specified document.
long	getVersion() Version number when this IndexReader was opened.
boolean	hasDeletions() Returns true if any documents have been deleted
boolean	hasNorms(String field) Returns true if there are norms stored for this field.
boolean	isCurrent() Check whether any new changes have occurred to the index since this reader was opened.
boolean	isDeleted(int n) Returns true if document n has been deleted
boolean	isOptimized() Checks is the index is optimized (if it has a single segment and no deletions).
int	maxDoc() Returns one greater than the largest possible document number.
byte[]	norms(String f) Returns the byte-encoded normalization factor for the named field of every document.
void	norms(String f, byte[] bytes, int offset) Reads the byte-encoded normalization factor for the named field of every document.
int	numDocs() Returns the number of documents in this index.
void	removeReaderFinishedListener(IndexReader.ReaderFinishedListener listener) Expert: remove a previously added IndexReader.ReaderFinishedListener.
TermDocs	termDocs() Returns an unpositioned TermDocs enumerator.
TermDocs	termDocs(Term term) Returns an enumeration of all the documents which contain term.
TermPositions	termPositions() Returns an unpositioned TermPositions enumerator.
TermEnum	terms() Returns an enumeration of all the terms in the index.
TermEnum	terms(Term t) Returns an enumeration of all terms starting at a given term.
String	toString()

Methods inherited from class org.apache.lucene.index.IndexReader

acquireWriteLock, clone, clone, close, commit, commit, decRef, deleteDocument, deleteDocuments, document, ensureOpen, flush, flush, getCommitUserData, getCommitUserData, getCurrentVersion, getIndexCommit, getRefCount, getTermInfosIndexDivisor, getUniqueTermCount, incRef, indexExists, lastModified, listCommits, main, notifyReaderFinishedListeners, numDeletedDocs, open, open, open, open, open, open, open, open, readerFinished, reopen, reopen, reopen, reopen, setNorm, setNorm, termPositions, undeleteAll

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

in

protected IndexReader in

Constructor Detail

FilterIndexReader

public FilterIndexReader(IndexReader in)

Construct a FilterIndexReader based on the specified base reader. Directory locking for delete, undeleteAll, and setNorm operations is left to the base reader.

Note that base reader is closed if this FilterIndexReader is closed.

Parameters:

in - specified base reader.

Method Detail

directory

public Directory directory()

Description copied from class: IndexReader

Returns the directory associated with this index. The Default implementation returns the directory specified by subclasses when delegating to the IndexReader(Directory) constructor, or throws an UnsupportedOperationException if one was not specified.

Overrides:

directory in class IndexReader

getTermFreqVectors

public TermFreqVector[] getTermFreqVectors(int docNumber)
                                    throws IOException

Description copied from class: IndexReader

Return an array of term frequency vectors for the specified document. The array contains a vector for each vectorized field in the document. Each vector contains terms and frequencies for all terms in a given vectorized field. If no such fields existed, the method returns null. The term vectors that are returned may either be of type TermFreqVector or of type TermPositionVector if positions or offsets have been stored.

Specified by:

getTermFreqVectors in class IndexReader

Parameters:

docNumber - document for which term frequency vectors are returned

Returns:

array of term frequency vectors. May be null if no term vectors have been stored for the specified document.

Throws:

IOException - if index cannot be accessed

See Also:

Field.TermVector

getTermFreqVector

public TermFreqVector getTermFreqVector(int docNumber,
                                        String field)
                                 throws IOException

Description copied from class: IndexReader

Return a term frequency vector for the specified document and field. The returned vector contains terms and frequencies for the terms in the specified field of this document, if the field had the storeTermVector flag set. If termvectors had been stored with positions or offsets, a TermPositionVector is returned.

Specified by:

getTermFreqVector in class IndexReader

Parameters:

docNumber - document for which the term frequency vector is returned

field - field for which the term frequency vector is returned.

Returns:

term frequency vector May be null if field does not exist in the specified document or term vector was not stored.

Throws:

IOException - if index cannot be accessed

See Also:

Field.TermVector

getTermFreqVector

public void getTermFreqVector(int docNumber,
                              String field,
                              TermVectorMapper mapper)
                       throws IOException

Description copied from class: IndexReader

Load the Term Vector into a user-defined data structure instead of relying on the parallel arrays of the TermFreqVector.

Specified by:

getTermFreqVector in class IndexReader

Parameters:

docNumber - The number of the document to load the vector for

field - The name of the field to load

mapper - The TermVectorMapper to process the vector. Must not be null

Throws:

IOException - if term vectors cannot be accessed or if they do not exist on the field and doc. specified.

getTermFreqVector

public void getTermFreqVector(int docNumber,
                              TermVectorMapper mapper)
                       throws IOException

Description copied from class: IndexReader

Map all the term vectors for all fields in a Document

Specified by:

getTermFreqVector in class IndexReader

Parameters:

docNumber - The number of the document to load the vector for

mapper - The TermVectorMapper to process the vector. Must not be null

Throws:

IOException - if term vectors cannot be accessed or if they do not exist on the field and doc. specified.

numDocs

public int numDocs()

Description copied from class: IndexReader

Returns the number of documents in this index.

Specified by:

numDocs in class IndexReader

maxDoc

public int maxDoc()

Description copied from class: IndexReader

Returns one greater than the largest possible document number. This may be used to, e.g., determine how big to allocate an array which will have an element for every document number in an index.

Specified by:

maxDoc in class IndexReader

document

public Document document(int n,
                         FieldSelector fieldSelector)
                  throws CorruptIndexException,
                         IOException

Description copied from class: IndexReader

Get the Document at the n ^th position. The FieldSelector may be used to determine what Fields to load and how they should be loaded. NOTE: If this Reader (more specifically, the underlying FieldsReader) is closed before the lazy Field is loaded an exception may be thrown. If you want the value of a lazy Field to be available after closing you must explicitly load it or fetch the Document again with a new loader.

NOTE: for performance reasons, this method does not check if the requested document is deleted, and therefore asking for a deleted document may yield unspecified results. Usually this is not required, however you can call IndexReader.isDeleted(int) with the requested document ID to verify the document is not deleted.

Specified by:

document in class IndexReader

Parameters:

n - Get the document at the n^th position

fieldSelector - The FieldSelector to use to determine what Fields should be loaded on the Document. May be null, in which case all Fields will be loaded.

Returns:

The stored fields of the Document at the nth position

Throws:

CorruptIndexException - if the index is corrupt

IOException - if there is a low-level IO error

See Also:

Fieldable, FieldSelector, SetBasedFieldSelector, LoadFirstFieldSelector

isDeleted

public boolean isDeleted(int n)

Description copied from class: IndexReader

Returns true if document n has been deleted

Specified by:

isDeleted in class IndexReader

hasDeletions

public boolean hasDeletions()

Description copied from class: IndexReader

Returns true if any documents have been deleted

Specified by:

hasDeletions in class IndexReader

doUndeleteAll

protected void doUndeleteAll()
                      throws CorruptIndexException,
                             IOException

Description copied from class: IndexReader

Implements actual undeleteAll() in subclass.

Specified by:

doUndeleteAll in class IndexReader

Throws:

CorruptIndexException

IOException

hasNorms

public boolean hasNorms(String field)
                 throws IOException

Description copied from class: IndexReader

Returns true if there are norms stored for this field.

Overrides:

hasNorms in class IndexReader

Throws:

IOException

norms

public byte[] norms(String f)
             throws IOException

Description copied from class: IndexReader

Returns the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.

Specified by:

norms in class IndexReader

Throws:

IOException

See Also:

AbstractField.setBoost(float)

norms

public void norms(String f,
                  byte[] bytes,
                  int offset)
           throws IOException

Description copied from class: IndexReader

Reads the byte-encoded normalization factor for the named field of every document. This is used by the search code to score documents.

Specified by:

norms in class IndexReader

Throws:

IOException

See Also:

AbstractField.setBoost(float)

doSetNorm

protected void doSetNorm(int d,
                         String f,
                         byte b)
                  throws CorruptIndexException,
                         IOException

Description copied from class: IndexReader

Implements setNorm in subclass.

Specified by:

doSetNorm in class IndexReader

Throws:

CorruptIndexException

IOException

terms

public TermEnum terms()
               throws IOException

Description copied from class: IndexReader

Returns an enumeration of all the terms in the index. The enumeration is ordered by Term.compareTo(). Each term is greater than all that precede it in the enumeration. Note that after calling terms(), TermEnum.next() must be called on the resulting enumeration before calling other methods such as TermEnum.term().

Specified by:

terms in class IndexReader

Throws:

IOException - if there is a low-level IO error

terms

public TermEnum terms(Term t)
               throws IOException

Description copied from class: IndexReader

Returns an enumeration of all terms starting at a given term. If the given term does not exist, the enumeration is positioned at the first term greater than the supplied term. The enumeration is ordered by Term.compareTo(). Each term is greater than all that precede it in the enumeration.

Specified by:

terms in class IndexReader

Throws:

IOException - if there is a low-level IO error

docFreq

public int docFreq(Term t)
            throws IOException

Description copied from class: IndexReader

Returns the number of documents containing the term t.

Specified by:

docFreq in class IndexReader

Throws:

IOException - if there is a low-level IO error

termDocs

public TermDocs termDocs()
                  throws IOException

Description copied from class: IndexReader

Returns an unpositioned TermDocs enumerator.

Note: the TermDocs returned is unpositioned. Before using it, ensure that you first position it with TermDocs.seek(Term) or TermDocs.seek(TermEnum).

Specified by:

termDocs in class IndexReader

Throws:

IOException - if there is a low-level IO error

termDocs

public TermDocs termDocs(Term term)
                  throws IOException

Description copied from class: IndexReader

Returns an enumeration of all the documents which contain term. For each document, the document number, the frequency of the term in that document is also provided, for use in search scoring. If term is null, then all non-deleted docs are returned with freq=1. Thus, this method implements the mapping:

Term => <docNum, freq>^*

The enumeration is ordered by document number. Each document number is greater than all that precede it in the enumeration.

Overrides:

termDocs in class IndexReader

Throws:

IOException - if there is a low-level IO error

termPositions

public TermPositions termPositions()
                            throws IOException

Description copied from class: IndexReader

Returns an unpositioned TermPositions enumerator.

Specified by:

termPositions in class IndexReader

Throws:

IOException - if there is a low-level IO error

doDelete

protected void doDelete(int n)
                 throws CorruptIndexException,
                        IOException

Description copied from class: IndexReader

Implements deletion of the document numbered docNum. Applications should call IndexReader.deleteDocument(int) or IndexReader.deleteDocuments(Term).

Specified by:

doDelete in class IndexReader

Throws:

CorruptIndexException

IOException

doCommit

protected void doCommit(Map<String,String> commitUserData)
                 throws IOException

Description copied from class: IndexReader

Implements commit.

Specified by:

doCommit in class IndexReader

Throws:

IOException

doClose

protected void doClose()
                throws IOException

Description copied from class: IndexReader

Implements close.

Specified by:

doClose in class IndexReader

Throws:

IOException

getFieldNames

public Collection<String> getFieldNames(IndexReader.FieldOption fieldNames)

Description copied from class: IndexReader

Get a list of unique field names that exist in this index and have the specified field option information.

Specified by:

getFieldNames in class IndexReader

Parameters:

fieldNames - specifies which field option should be available for the returned fields

Returns:

Collection of Strings indicating the names of the fields.

See Also:

IndexReader.FieldOption

getVersion

public long getVersion()

Description copied from class: IndexReader

Version number when this IndexReader was opened. Not implemented in the IndexReader base class.

If this reader is based on a Directory (ie, was created by calling IndexReader.open(org.apache.lucene.store.Directory), or IndexReader.reopen() on a reader based on a Directory), then this method returns the version recorded in the commit that the reader opened. This version is advanced every time IndexWriter.commit() is called.

If instead this reader is a near real-time reader (ie, obtained by a call to IndexWriter.getReader(), or by calling IndexReader.reopen() on a near real-time reader), then this method returns the version of the last commit done by the writer. Note that even as further changes are made with the writer, the version will not changed until a commit is completed. Thus, you should not rely on this method to determine when a near real-time reader should be opened. Use IndexReader.isCurrent() instead.

Overrides:

getVersion in class IndexReader

isCurrent

public boolean isCurrent()
                  throws CorruptIndexException,
                         IOException

Description copied from class: IndexReader

Check whether any new changes have occurred to the index since this reader was opened.

If this reader is based on a Directory (ie, was created by calling IndexReader.open(org.apache.lucene.store.Directory), or IndexReader.reopen() on a reader based on a Directory), then this method checks if any further commits (see IndexWriter.commit() have occurred in that directory).

If instead this reader is a near real-time reader (ie, obtained by a call to IndexWriter.getReader(), or by calling IndexReader.reopen() on a near real-time reader), then this method checks if either a new commmit has occurred, or any new uncommitted changes have taken place via the writer. Note that even if the writer has only performed merging, this method will still return false.

In any event, if this returns false, you should call IndexReader.reopen() to get a new reader that sees the changes.

Overrides:

isCurrent in class IndexReader

Throws:

CorruptIndexException - if the index is corrupt

IOException - if there is a low-level IO error

isOptimized

public boolean isOptimized()

Description copied from class: IndexReader

Checks is the index is optimized (if it has a single segment and no deletions). Not implemented in the IndexReader base class.

Overrides:

isOptimized in class IndexReader

Returns:

true if the index is optimized; false otherwise

getSequentialSubReaders

public IndexReader[] getSequentialSubReaders()

Description copied from class: IndexReader

Expert: returns the sequential sub readers that this reader is logically composed of. For example, IndexSearcher uses this API to drive searching by one sub reader at a time. If this reader is not composed of sequential child readers, it should return null. If this method returns an empty array, that means this reader is a null reader (for example a MultiReader that has no sub readers).

NOTE: You should not try using sub-readers returned by this method to make any changes (setNorm, deleteDocument, etc.). While this might succeed for one composite reader (like MultiReader), it will most likely lead to index corruption for other readers (like DirectoryReader obtained through IndexReader.open(org.apache.lucene.store.Directory). Use the parent reader directly.

Overrides:

getSequentialSubReaders in class IndexReader

getCoreCacheKey

public Object getCoreCacheKey()

If the subclass of FilteredIndexReader modifies the contents of the FieldCache, you must override this method to provide a different key

Overrides:

getCoreCacheKey in class IndexReader

getDeletesCacheKey

public Object getDeletesCacheKey()

If the subclass of FilteredIndexReader modifies the deleted docs, you must override this method to provide a different key

Overrides:

getDeletesCacheKey in class IndexReader

toString

public String toString()

Overrides:

toString in class IndexReader

addReaderFinishedListener

public void addReaderFinishedListener(IndexReader.ReaderFinishedListener listener)

Description copied from class: IndexReader

Expert: adds a IndexReader.ReaderFinishedListener. The provided listener is also added to any sub-readers, if this is a composite reader. Also, any reader reopened or cloned from this one will also copy the listeners at the time of reopen.

Overrides:

addReaderFinishedListener in class IndexReader

removeReaderFinishedListener

public void removeReaderFinishedListener(IndexReader.ReaderFinishedListener listener)

Description copied from class: IndexReader

Expert: remove a previously added IndexReader.ReaderFinishedListener.

Overrides:

removeReaderFinishedListener in class IndexReader